How to show values in ggplot instead of geom

Question

I have a dataset that looks as follows:

cluster <- c(rep(c(1:4), 2))
score <- c(1.3, 7.2, 4.9, 7.5, 6.8, 4.1, 9.9, 5.8)
x_axis <- c(rep("indicator1", 4), rep("indicator2", 4))

dt <- data.table(cluster, score, x_axis)

and I am plotting the score for each indicator by cluster:

ggplot() +
  geom_point(data=dt, aes(x=x_axis, y=score))

I would like to do one of the following:

1. Replace the dots in the plot with cluster number (or put the number next to the dot), or
2. Use different shapes/color for each cluster and add a legend below the plot, indicating to which cluster does each shape correspond to.

How can I do this?